How to tell wxpython to add a text control to the right sizer

Question

In the code below I am trying to dynamically add new text controls to a sizer. I have two sizers, one on the left ("sizer") and one on the right ("sizer2"). There is a function called "add_region" which should add the new text control to the sizer on the right (sizer2). I have bound this function to the button "button_add". When I call the function add_region directly from the main body of the code ( line: self.add_region(0) ), the text control is added to sizer2 as desired. However, the same function is called by hitting the button, the text control is put in a different sizer (presumably "sizer"). Why does the position of the text control depend on the way in which the function is called?

#!/usr/bin/python
# -*- coding: utf-8 -*-
#
#This is a good tutorial: http://wiki.wxpython.org/wxPython%20by%20Example

import wx
import wx.lib.scrolledpanel



class region():

    #variables associated with the entire class (not each object)
    nreg=0

    def __init__(self,Ani=999.0e29,AZ=9.99):

        self.Ani=Ani
        self.AZ=AZ
        # self.text_Ani
        region.nreg+=1



class MainWindow(wx.Frame): #A "frame" is what we normally think of as a window, so we have called it MainWindow



    def __init__(self, parent, title):    
        super(   MainWindow, self).__init__(parent, title=title, size=(450, 350)   )

        self.dirname = ''
        self.ibox=0
        self.iv=0 #the vertical depth on the LHS
        self.iw=0 #the vertical depth on the RHS
        self.Aregion_objects=[]
        self.Ani=[] #array of ion number densities
        self.AZ=[]
        self.Axmin=[]
        self.Axmax=[]
        self.Aymin=[]
        self.Aymax=[]
        self.text_Ani=[]
        self.tc_Ani=[]
        self.sizer = wx.GridBagSizer(5, 1)
        #also declare a sizer that will contain all the regions on the LHS (sizer2)
        self.sizer2 = wx.GridBagSizer(1, 1)
        #self.SetMinSize(self.GetSize()) #prevents the window from being made arbitrarily small
        self.SetClientSize( (900,900) )
        self.SetMinSize( (-1,-1) )
        self.InitGUI()
        self.Centre()
        # self.SetupScrolling()
        self.Show()     



    def InitGUI(self):



        screenSize = wx.DisplaySize()
        screenWidth = screenSize[0]
        screenHeight = screenSize[1]


        self.panel = wx.lib.scrolledpanel.ScrolledPanel(self)
        # self.panel.Layout()
        self.panel.SetupScrolling()

        font_title = wx.Font(10, wx.DECORATIVE, wx.NORMAL, wx.BOLD)

        #self.panel.SetBackgroundColour('#4f5049')

        #a sizer is a way of laying out widgets, it is not a window in itself.
        # This is why we create widgets in the self.panel (by using "self.panel" as the parent), then afterwards add the widget to the sizer.
        sizer = self.sizer #wx.GridBagSizer(5, 1)
        #also declare a sizer that will contain all the regions on the LHS (sizer2)
        sizer2 = self.sizer2 #wx.GridBagSizer(1, 1)
        # sizer = wx.BoxSizer()

        #make a horizontal box dividing the page into left and RHS. We will put the gridbagsizer into the
        #LHS and the target picture into the RHS of the hbox
        hbox = wx.BoxSizer(wx.HORIZONTAL)
        hbox.Add(sizer,2) #add the box to the current window (self)


        #make a vertical box that will contain the stuff on the RHS
        vbox_RHS = wx.BoxSizer(wx.VERTICAL)
        hbox.Add(vbox_RHS,2) #add the vbox into the hbox, so it now takes up the 2nd position in the hbox (the gridbagsizer took the first)

        text_view = wx.StaticText(self.panel, label="Target View")
        text_view.SetFont(font_title)
        vbox_RHS.Add(text_view, flag=wx.TOP|wx.LEFT|wx.BOTTOM,border=15)
        self.iw+=1

        button_redraw = wx.Button(self.panel, label="Redraw")
        self.Bind(wx.EVT_BUTTON, self.redraw_pic, button_redraw)
        vbox_RHS.Add(button_redraw)
        self.iw+=1

        self.pic = wx.StaticBitmap( self.panel, -1, wx.Bitmap("small1.jpg", wx.BITMAP_TYPE_ANY),size=(400,250) )
        vbox_RHS.Add(self.pic)
        self.iw+=1



        vbox_RHS.Add(sizer2)






        button_check = wx.Button(self.panel, label="Check")
        self.Bind(wx.EVT_BUTTON, self.check_all, button_check)
        sizer.Add(button_check, pos=(self.iv, 0))
        self.iv+=1



        text_PIC = wx.StaticText(self.panel, label="Main PIC Options")
        text_PIC.SetFont(font_title)
        sizer.Add(text_PIC, pos=(self.iv, 0), flag=wx.TOP|wx.LEFT|wx.BOTTOM,border=15)
        self.iv+=1





        self.tc_info = wx.TextCtrl(self.panel)
        sizer.Add(self.tc_info, pos=(self.iv, 1), span=(1, 3), flag=wx.TOP)
        self.iv+=1

        self.add_region(0)

        button_add = wx.Button(self.panel, label="Add Region")
        self.Bind(wx.EVT_BUTTON, self.add_region, button_add)
        vbox_RHS.Add(button_add)
        self.iw+=1





        sizer.AddGrowableCol(2)

        self.panel.SetSizer(hbox)



    # GUI EVENTS
    def checkBtnClick(self, e):
        self.tc_info.SetValue("blahh")



    def check_all(self, e):
        self.read_all()






    #----------------------------------------------------------------------
    def redraw_pic(self, e):
        #blah
        print "Redraw called"

    def save_all(self, event):
        saveFileDialog = wx.FileDialog(self, "Save As", "", "","Python files (*.py)|*.py",wx.FD_SAVE | wx.FD_OVERWRITE_PROMPT)
        saveFileDialog.ShowModal()
        saveFileDialog.GetPath()
        saveFileDialog.Destroy()

    def read_all(self):

        # self.ibox=0 #increases each time a new box is added
        # self.nbox=0 #number of boxes currently on the page (accounts for fact some may have been deleted)
        # self.Aid=[]
        # self.Apresent=[]

        self.l_hybrid=0
        self.l_colls=0
        self.l_implicit=0
        self.l_damp_bounds=0
        self.l_cold=0
        self.l_laser_const=0
        # self.nppc=self.tc_nppc.GetValue()
        self.nx=self.tc_nx.GetValue()
        self.nsp=self.tc_nsp.GetValue()
        self.xmax=self.tc_xmax.GetValue()
        self.nmin=self.tc_nmin.GetValue()
        self.inten=self.tc_inten.GetValue()
        self.Ti_init0=self.tc_Ti_init0.GetValue()
        self.Ti_init1=self.tc_Ti_init1.GetValue()
        self.mi=self.tc_mi.GetValue()
        self.tout=self.tc_tout.GetValue()
        self.gaussian_cutoffs=self.tc_gaussian_cutoffs.GetValue()
        self.t_FWHM=self.tc_t_FWHM.GetValue()


        print "nppc=",self.nppc
        print "t_FWHM=",self.t_FWHM

    # def add_region(self,e):
    #     #blah
    #     print "add called"

    def add_region(self,event):
        print "add_region called"

        # i=self.ibox
        i=region.nreg
        sizer=self.sizer2
        reg=region(Ani=0.0,AZ=0.0)
        self.Aregion_objects.append(reg)
        print "add_region:iw=",self.iw

        font_title = wx.Font(10, wx.DECORATIVE, wx.NORMAL, wx.BOLD)

        text_region = wx.StaticText(self.panel, label="Region "+str(i))
        text_region.SetFont(font_title)
        sizer.Add(text_region, pos=(self.iw, 0), flag=wx.TOP|wx.LEFT|wx.BOTTOM,border=15)
        self.iw+=1




if __name__ == '__main__':

    app = wx.App()
    MainWindow(None, title="")
    app.MainLoop()

Answer 1

I din't really dig too much into this but I was able to fix it by adding:

self.panel.Layout()
event.Skip()

to the end of add_region. The reason for this is because when you add things to a sizer, you have to tell it that the layout has changed, hence a call to self.panel.Layout.(Notice how this is a call for the panel and not the Frame itself) class. The event.Skip() tells wx to check if it needs to do anything else when a certain event type is launched, in this case it checks if it needs to anything else after the button is pushed.

One quick note that I should say is that it's best to separate the Frame and Panel instances to a class on their own. That way panels are potentially reusable, and more organized code plus best practice :p If your just messing around with wx then this is fine, but just a little note :)

Hope this helps